In recent years the demand for transparent conductive laminates for use as transparent electrodes, which are essential components of touch panels or capacitive switches for various electronic devices, has been increasing. Transparent conductive laminates include a transparent substrate and a transparent conductive film formed from an ink composition containing a conductive polymer, which is stacked on the substrate. These transparent conductive films can be prepared by known methods such as offset printing and screen printing. These printing methods, which do not require any complicated process, allow for easy patterning at low costs, and therefore have quite excellent productivity.
Offset printing, among these, is attracting interest as a method allowing printing on three-dimensional objects. In particular, gravure offset printing allows drawing of fine line patterns and is therefore suitable for forming transparent electrode interconnects of capacitive touch panels or touch sensors, which require fine line patterns, but on the other hand it cannot disadvantageously produce thick coatings but can only provide limited coating thicknesses due to its process requirements. Therefore, if a usual ink composition with a low solids content is used in this printing process, the transparent conductive film thus prepared disadvantageously has a low dry film thickness and a high surface resistivity. In addition, usual ink compositions, which are aqueous compositions, have the drawback of poor wettability on blankets.
Meanwhile, pad printing has the advantage of allowing printing also on complex three-dimensional objects.